A variety of tools and technologies are presently available for navigating in geographical spaces. Global Positioning System (GPS) is a well known technology that sees prevalent use in navigating in geographical spaces. Cellular triangulation is another technology that is used either as an assistive method to GPS navigation or as a stand-alone method for navigation.
Navigating in geographical spaces essentially uses two things—a map of the geographical space, and a location of the navigation device in that map. Generally, a map database provides the mapping data for the first part, and GPS or other technology provides the navigating device's location relative to that mapping data.
Geographical spaces include boundaries. These boundaries are defined in a variety of ways. For example, countries have boundaries or borders relative to other countries. Similarly, states or provinces within a country have boundaries with other states or provinces. Likewise, cities, town, and suburbs have boundaries. Airspace boundaries exist in the air and maritime boundaries exist in navigable waters.
Furthermore, the boundaries can be interpreted in other ways as well. For example, the premises of a sporting arena have a boundary, a perimeter of a building is a boundary, and an area within a building also has boundary.
Some boundaries are visible to humans, and other boundaries are not. For example, a boundary on land between countries can be visibly marked with physical markers, or can be unmarked and therefore invisible. A boundary in a water body is often not marked with visible markers. Vast land areas including several real properties may not have visible markings demarcating one property from another.
Navigation maps are capable of representing some boundaries that are otherwise invisible in a physical form in the geographical space. For example, maps show continuous boundaries between countries, over land, in water, and in the air, regardless of whether corresponding boundaries are physically marked in the corresponding geographical space.